Known in the prior art is a device for taking samples of bottom sediments from water basins, comprising a vertical coring tube with a closed upper end provided with a check valve, a ballast weight on the upper end of the coring tube and the side stationary supports (cf. USSR Inventor's Certificate No. 1,013,810, class G01N, 1/10, published in 1983).
However, under the conditions of rough water in water basins such a device fails to provide a guaranteed sampling as water masses in the volume of a wave move upwards at a speed greater than that of the device proper, because of which the check valve in the upper end of the coring tube gets opened and the taken sample is partially or even completely lost. Under the conventional conditions the sample is retained in the coring tube due to the fact that with the device being lifted, the check valve is closed and the reduced pressure is built up in the space between the closed upper end of the coring tube and the sample contained therein.
Also known in the prior art is a device for taking samples of bottom sediments from water basins, comprising a vertical coring tube with a closed upper end provided with a check valve and a means for preventing the loss of a taken sample in the process of the device lifting (cf. USSR Inventor's Certificate No. 623,128, class G01N, 1/04, published in 1978).
In the known device the coring tube is made in the form of two concentrically installed tubes, the internal tube being intended for filling with a taken sample. As to a means for preventing the loss of a taken sample, a valve is used. The valve is installed at the cutting shoe and is made in the form of two flaps closing under the action of the springs. Before the device sinking onto the bottom of a water basin the flaps are cocked. The device sinks in the soil under the action of the weight thereof. The column of the soil, moving upwards in the cavity of the tube, completely opens the valve flaps, releasing them from the cocking stop, and fills the internal tube. While lifting the device the valve flaps close under the action of the springs and the weight of the taken sample. The known device prevents the loss of a taken sample in the process of lifting. However, the natural structure of bottom sediment layers is disturbed. This results from the following. The valve flaps are, prior to sampling, in a half-open position and open completely only under the action of the force developed by the column of the sample moving upwards. The weak layers (especially the surface layer) are not able to stand the force needed for the complete opening of the flaps, in the zone of the valve flaps the section for the sample passing is decreased and as a result, the compression and intermixing of the sample takes place, leading to the disturbance of the initial structure of the sample layers.
The invention is aimed at providing a device for taking samples of bottom sediments from water basins with a means for preventing the loss of a taken sample in the process of the device lifting of such a design which will ensure an undisturbed natural structure of the bottom sediment layers in the taken sample.